Burriss starting at second base; Tejada, Sanchez, Posey sit

We learned something today. Reliever Javier Lopez has a mantra. He likes to think about “the relentless flow of the positive river.”

For the Giants right now, the river is flowing backwards. They have lost five of six going into today’s series finale against Pittsburgh, which begins at 9:35 a.m. PDT. This offense is paddling against the current.

Today’s lineup looks a lot different. Miguel Tejada, Freddy Sanchez and Buster Posey are sitting. Just-recalled Emmanuel Burriss is playing second base and Mike Fontenot is at short. Eli Whiteside is catching. Manager Bruce Bochy wanted to get a little more left-handed.

Before I let you go to eat your Cap’n Crunch, I wanted to get into rumors yesterday that the Marlins were after Mark DeRosa (this before he was placed on the DL).

It might seem like he’s a waste of roster space even if healthy because he never plays, but remember, the Giants have had five off days already. There hasn’t been much need to rest starting position players. That changes, of course. On Tuesday, the Giants began a stretch of 46 games broken up by only two off days.

Pablo Sandoval is playing great ball. He looks rejuvenated. But he is going to need rests now and again, and DeRosa is his primary backup (though Fontenot and Burriss can play 3B).

I broached the idea of a DeRosa trade with general manager Brian Sabean yesterday. He said he can’t think about trading him now because the Giants will need the depth he provides — if his wrist allows him to hit.

There would be two compelling reasons to trade DeRosa: 1) A team is willing to take on most of what remains of his $6 million salary. 2) A team is willing to send the Giants a super-good prospect if Sabean agrees to pay DeRosa’s contract.

Yes, I’m told, the Marlins have had internal discussions about acquiring DeRosa to be their third baseman. No, I have no confidence they want to spend the money to pay DeRosa, nor part with a blue-chip prospect for a 36-year-old player who has had two wrist surgeries and now has inflammation.